Cooling systems are commonly utilized throughout the world for cooling devices and/or environments. As is well known, a cooling system can be to keep occupants in a structure comfortable. A well known example of this type of cooling system is an air conditioner for a home or office.
Alternately, instead of providing comfort to the occupants, many cooling systems are used to enhance or facilitate the operation of a device or a piece of equipment. In fact, a number of devices are unable to properly function without being cooled by a cooling system. For example, devices which utilize superconductors are unable to operate without a cooling system. The term superconductivity refers the state in certain metals, alloys and ceramics in which electrical resistance is zero. In order to attain superconductivity, the certain metal, alloys and ceramics must be cooled to a temperature near or above absolute zero. Importantly, if the temperature of these certain materials raises above the required superconducting temperature, these materials cease to function as a superconductor.
In recent years, the use of superconductors for MRI Systems has become increasingly popular. Typically, the MRI system includes a magnetic coil composed of superconducting wire that is maintained at the required superconducting temperature by a cooling system. The widespread use of superconductors in MRI Systems is due to the ability to offer a combination of high field strength, low power consumption and relatively low mass.
A typical cooling system for a superconductor includes a vessel holding a cryogenic fluid refrigerant. The vessel is utilized to deliver a continuous flow of the cryogenic fluid refrigerant to the superconductor to maintain the superconductor at the required superconducting temperature. A detailed description of one type of cryogenic cooling system for a superconductor of a MRI System is provided in U.S. Pat. No. 5,417,073, which issued to James et al. The contents of U.S. Pat. No. 5,417,073 are incorporated herein by reference.
Unfortunately, present cooling systems lack an easy and reliable way to control the flow of the cryogenic fluid refrigerant to the superconductor. Importantly, if flow of the fluid refrigerant is insufficient, the temperature of the material will rise above the required superconducting temperature and the material will cease to function as a superconductor. Alternately, if too much of the fluid refrigerant is delivered to the superconductor, the cooling system will waste fluid refrigerant. This will result in increased cost for operating the cooling system and reduced operational time for the cooling system.
In light of the above, it is an object of the present invention is to provide a system and method for regulating the flow of a fluid refrigerant from the vessel to the cooling elements of an MRI device or other environment. Yet another object of the present invention to provide a system and method for regulating the temperature of the cooling element which is relatively easy to operate and relatively inexpensive to manufacture. Still another object of the present invention is to provide a system and method for regulating the temperature of the cooling element which requires very few, if any, moving components and is not electrically complicated. Yet another object of the present invention is to provide a cooling system which is more efficient, which is thermally stable and which can operate for longer periods of time than existing cooling systems.